1. Field of the Invention
The present invention relates to an apparatus for transmitting and receiving a message between processors for a distributed type processing system and a method therefor.
2. Description of the Background Art
Generally, a communication method between processors for a conventional distributed type processing system is implemented using a sliding-window flow control protocol capable of transmitting and receiving a message of a size N of an existing window, namely, a certain size for continuously transmitting a message between processors at one time, based on a selective ARQ(Automatic Repeat reQuest) method.
In other words, if there is a message to be transmitted to the opponent processor, it is judged whether there is an empty slide at a window of the destination. If more than one slide is empty, the message is immediately transmitted. If there is not the empty slide, the message is temporarily stored in a send queue. If there is an empty slide, the message is transmitted thereto based on the sliding window flow control protocol. In the thusly constituted conventional distributed type processing system, the state of the window slide based on the sliding window flow protocol when a message is transmitted and received between processors for the conventional distributed type processing system will be explained with refernce to FIG. 1.
FIG. 1 illustrates a case that a message is transmitted from a first processor to a second processor. At an initial state for transmitting and receiving a message between processors, the window memories of the first and second processors are empty, namely, the window slides 0xcx9c7 are empty. In this state, the message is stored into the window slides 0, 1, and 2 for transmitting the message to the first and second processors, respectively. When the messages F0, F1, and F2 are transmitted to the second processor side, since the second processor receives the message at the window slides 0, 1, and 2, the window slides 3xcx9c7 of the first and second processors are emptied.
At this time, an ACK3 signal with respect to the window slide number which is received in the future by the second processor is transmitted to the first processor, and at the same time, the window slides 3xcx9c10 are emptied. The first processor receives an ACK3 signal from the second processor, and the window slides 3xcx9c10 are emptied.
In order to transmit a message from the first processor to the second processor, when the message is stored into the window slides 3xcx9c6 the window slides 7xcx9c10 continuously remain empty. If the messages F3xcx9cF6 stored in the window slides 3xcx9c6 are transmitted from the first processor to the second processor, the second processor receives the message and processes the same. As the second processor receives the message F3 of the window slide 3, when an ACK4 signal with respect to the window slide number which is received at the next time is transmitted to the first processor, the second processor continuously receives the messages F4xcx9cF6 from the first processor in a state that the window slides 4xcx9c11 are empty, so that the window slides 7xcx9c11 are emptied.
At this time, the first processor receives the ACK4 signal from the second processors. Since the window slides 4xcx9c6 are in use, the window slides 7xcx9c11 are emptied.
However, in the conventional distributed type processing system, in the case of transmitting a short message for a short time, the transmission efficiency is decreased. In order to overcome the above-described problem, when the size of the window slide is increased, the error recover algorithm is complicated. Since the size of each message is not uniform, the size of the message buffer is determined by the size of the longest message.
Accordingly, it is an object of the present invention to provide an apparatus for transmitting and receiving a message between processors for a distributed type processing system and a method therefor which are capable of increasing a message transmission efficiency in the distributed type processing system and enhancing a communication performance by transmitting a plurality of short messages packed at a certain size by a transmission and receiving side processor when transmitting and receiving a message between processors for a distributed type processing system and unpacking the packed messages at the receiving side processor in older to overcome the problems encountered in the conventional art.
In order to achieve the above objects, there is provided a distributed type processing system which performs a real time communication between a plurality of processor and includes a packing unit for packing a plurality of messages in a certain message format when transmitting the messages and transmitting the packed messages to another processor, and an unpacking unit for judging an information stored in a certain message format when receiving a message from the another processor and unpacking the plurality of the packed messages, wherein said packing and unpacking units are provided in each processor.
Additional advantages, objects and features of the invention will become more apparent from the description which follows.